if you do MMA, i would lean more towards: NOTHING. I used to compete in MMA till an armbar tore some of my shoulder tendons, and i got sucked into the whole 'whatever should make stronger would make me a better fighter' mentality. turns out, competing at your natural weight or under, and focusing on cardio and flexibility, is the best way to go. i took Andromass to make me 'all big and strong' and bump up to 205lb division, and while my strength and size gains DID go through the roof (i gained 12kgs in 10weeks), my cardio sucked balls, the natural 205'ers threw me around like a doll in the sparring sessions, and when it came to the ground work i was absolutely useless.
take it from a guy that has been down your road and made this mistake: focus on agility and endurance, and above all technique, it doesnt matter how big and strong you are, if you dont know what the hell you're doing, especially when it comes to the ground game, youre going to be destroyed, look what happend to brock lesnar when he first came to the UFC; he thought he could monster people with his speed and size, and then a simple bjj move made him tap out. You think an external source of testosterone will keep your hands up and stop that headkick, or keep you moving around the cage and stuff that single-leg takedown? wont happen. besides look at the all the juicers in the UFC, how many of them (aside from the heavyweights) are successful? bonnar, leben both got busted, and did you see the fights they had whilst on it? their cardio and performance SUCKED. finially, how would u feel if u got busted and you would always have that stigma over your head, and do you want to credit any wins you have to anything other than your own personal ability? Upon reflection of my actions i would rather win through technique and skill and not have that thought of 'if i didnt take this i wouldnt have won' in the back of my mind...
Edit: your stats say 6ft 4 and 190? you could easily dominate in the 185 division, at your height you should have great reach advantage, i dont know what its like in the States, but here in oz, most of the guys that are in the 185lb division arent taller than 6ft